Recent developments of medical technologies include imaging techniques using tomography on dynamics of tracer molecules in vivo. For example, a positron emission tomography, or PET, has been in practical use (Non-patent Document 1). In PET imaging devices, detection will be made on gamma rays that are emitted through pair annihilation, which is caused by a collision of a positron with an electron in surrounding medium, where the positron is emitted from nuclei of radio isotopes which decay with positron decaying, or positron emitting nuclei. As a result of the pair annihilation two pencils of gamma ray each having energy of 511 keV are emitted into opposite directions, or directions forming substantially 180 degrees angle in between. Generally speaking in PET imaging devices, two or more detectors detect gamma rays in coincidence, and thereafter distributions of the positron emitting nuclei are reconstructed based on the coordinates of detectors that have detected them in coincidence. To be more specific, a medicine to accumulate in cancer cells, is labeled by positron emitting nuclei; the medicine is administered to a living body, or a subject; and the PET imaging device captures in vivo image. This allows imaging of a three-dimensional distribution of cancer cells inside the subject's body, for example.
On the other hand, according to the developments in life science or biomedical science it has been revealed that complex interrelated dynamics among a plurality of molecules is actually underlying activities of living organisms, and moreover, and such dynamics would be related to initiation of lesions.